Examples

OBE provides some example workflows which illustrate the various XPDL capabilities and OBE extensions.

Document Approval: A workflow that automates the approval chain for a piece of sales or marketing collateral. It shows a chain of activities performed by humans with the aid of a browser-hosted worklist handler and a WebDAV document repository.
New Employee: A workflow that automates IT provisioning for a new employee by invoking a series of enterprise services.
Enterprise Application Integration: A fully-automated straight-through ('STP') data transformation process. A workflow is triggered by an inbound XML message which it transforms using XSLT then forwards to an external destination.
Travel Bookings: A workflow that automates composite travel bookings. Illustrates compensating transactions for long-running business transactions (sagas).
WfMC Sample Workflow: The WfMC's Sample Workflow Process. This is a sales order processing scenario where customers pay either by credit card or credit account.

Deployment and Execution

The example workflows can either be executed by the basic workflow engine or by the J2EE workflow server. The shell scripts are all in


    $OBE_HOME/bin

and can either be executed from a console window or invoked directly by clicking on them in your OS's native graphical file explorer.

Tip: When working from a console window, cd to the $OBE_HOME/bin directory and establish the OBE client environment for your shell by executing .\obeinit (Windows) or . ./obeinit (Unix/Linux). Having done this you can then change to other directories and execute OBE scripts directly without having to provide qualified paths.

Basic Workflow Engine

Select the example configuration by executing examples.
Start the command line worklist by executing clworklist.
Set the client protocol to local (menu option 1).
Connect to OBE (menu option 2). This will start a local, in-memory copy of the workflow engine.
The example workflows will all be deployed automatically because the BasicProcessRepository scans and auto-deploys *.xpdl files in the $OBE_HOME/examples/config/processes directory.
To start a workflow manually:

Navigate to Workflow Processes (menu option 4).
Instantiate the process of your choice (menu option 2).
Provide workflow startup data (the 'formal parameters').
Quit back to the main menu.

To start an event-triggered workflow:

Copy/paste or drag/drop a data file from $OBE_HOME/examples/etc/* to the $OBE_HOME/examples/config/events directory (being sure to hold down the control key to copy the file rather than move it).
The BasicApplicationEventBroker should detect and read the file, raising the event and instantiating the workflow.

Navigate to Worklist (menu option 5) then list and execute work items as appropriate to the workflow.

J2EE Workflow Server

Configure the application server and deploy $OBE_HOME/j2ee/lib/ obeserver.ear.
Select the example configuration by executing examples.
Start the application server by executing startas.
Start the command line administrator by executing cladmin.
Set the client protocol to rmi (menu option 1)

The JNDI Factory should be correct for your application server. If it is not, this means you didn't configure OBE properly. You are recommended to quit and re-run $OBE_HOME/prepare, specifying appropriate properties.

Connect to OBE (menu option 2). This will create a remote connection to the workflow server.

When prompted, supply Host URL, User ID and Password. If the defaults are not correct you can quit and re-run $OBE_HOME/prepare, specifying appropriate properties, or you can simply type them in.

Navigate to Process Definitions (menu option 4).
For each workflow you wish to work with:

Import the appropriate XPDL package (menu option 3). The example workflows are located in the $OBE_HOME/examples/config/processes directory. You can drag/drop the file from a graphical explorer window onto the console window to save typing the file name in.

Start your web browser and point it to the OBE Web Worklist at http://localhost:8080/obeworklist/ (substituting an appropriate host name and port, depending on your application server). Log in as the workflow participant whose role you wish to assume. If you log in as 'system' (default password ' password'), you will have access to all functionality.
To start a workflow manually:

Click on the Processes link.
Click on the ID of the process of your choice then click on Instantiate.
Provide workflow startup data ('formal parameters') as prompted.

To start an event-triggered workflow:

Send a data file to the OBE JMS application event queue by executing the send shell script from $OBE_HOME/examples/etc/*, supplying the file name as an argument.
The EJBApplicationEventBroker will receive the data through JMS, raising an application event and instantiating the workflow.

Once the workflow is started, you can explore its attributes, activity instances and their associated work items, executing and/or marking them complete and thereby drive the process instance to completion.
To view the audit trail for a work item, activity or process instance, click on the corresponding 'History' link in the Web Worklist or execute the 'History' command in the Command Line Worklist.

Manual vs. Triggered Process Instantiation

Most of the example workflows can be either started manually using a worklist handler client or triggered by an asynchronous application event. Typically the <WorkflowProcess> declares at least one <FormalParameter>, meaning that the corresponding process attribute must be assigned a value before a newly created process instance can be started. Event-triggerable workflows initialize this mandatory process attribute from an OUT-mode event parameter.

Execution Tracing

OBE uses Log4J via Apache Commons Logging to log workflow enactment activity. You can enable DEBUG-level logging to see the fine detail of workflow, activity and work item execution, by setting the logging level in log4j.properties thus:

# OBE engine.
log4j.logger.org.obe.engine=DEBUG

# OBE repositories.
log4j.logger.org.obe.engine.repository=DEBUG

# OR simply enable all OBE logging:
log4j.logger.org.obe=DEBUG

Alternatively you can set the logging level via JMX if your application server supports it. JBoss does; you can access the Log4J Service's MBean via the JBoss JMX web console.

Viewing and Editing the Example Workflows

You may wish to open the example workflows in a purpose-written XPDL editor such as Enhydra's JaWE in order to follow the process descriptions more clearly. The JPEG images in this documentation show the activity/transition networks but lack some important details.

Feel free to experiment by editing and redeploying the example workflows. You can either just edit the raw XML in a text editor, or use a generic syntax-directed XML instance editor, or use JaWE. You can edit the workflow in place (i.e., at $OBE_HOME/examples/config/processes) but you might wish to make a backup copy in a different directory before changing anything. The BasicProcessRepository in the basic OBE configuration will detect changed changed process definitions and automatically redeploy them. If you are running the OBE J2EE Server configuration it will be necessary to manually redeploy using the cladmin client (it is not recommended to use the BasicProcessRepository in the J2EE server configuration because the former uses Java file I/O and allocates threads, both of which techniques are expressly forbidden to EJBs by the J2EE specifications).

Credits

John Wiley & Sons

The Document Approval and New Employee workflows are reproduced with kind permission from John Wiley & Sons. They were developed by OBE's author Adrian Price as a contribution to the recent publication:

Process-Aware Information Systems - Bridging People and Software Through Process Technology, Marlon Dumas, Wil M. van der Aalst, Arthur H. ter Hofstede, John Wiley & Sons, 2005. ISBN: 0-471-66306-9.

Workflow Management Coalition

The WfMC Sample Workflow is reproduced with kind permission from the Workflow Management Coalition.

Enhydra Community

The workflow diagrams were created with the use of the Open Source Java Workflow Editor - JaWE. Many thanks to the Enhydra team for graciously making a few changes to enable JaWE to support OBE.

Definitions

WebDAV: Web-based Distributed Authoring and Versioning, an HTTP extension protocol supported by word processors etc. See http://www.ietf.org/rfc/rfc2518.txt
XFORMS: XML Forms language, the W3C's powerful successor to traditional HTML forms. See http://www.w3.org/TR/xforms
XSL: Extensible Stylesheet Language, for transforming XML documents. See http://www.w3.org/Style/XSL/
WSDL: Web Service Description Language. See: http://www.w3c.org/2002/ws/